Laundry detergent powder manufacturers seek to provide products that have excellent whiteness and dingy cleaning performance. In order to meet this need, laundry detergent powder manufacturers incorporate ingredients such as hueing agents and detersive surfactants into their products. There are many different types of hueing agents and surfactants available to the laundry detergent manufacturer and there are a variety of different methods these ingredients can be incorporated into a laundry detergent powder product. Particular care needs to be taken when incorporating hueing agents into a laundry detergent powder product to ensure that good hueing performance is achieved. In particular, it is desirable to have an even distribution of hueing agent on the fabric surface. Furthermore, care must be taken to minimize any undesirable spotting negatives.
The inventors have found that the resultant whiteness and dingy cleaning performance of the laundry detergent powder depends not only on the combination of the type of hueing agent and the type of detersive surfactant incorporated, but also on the particle architecture of the hueing agent particle and the detersive surfactant particle.
The inventors have found that when this particle architecture is optimized as defined by the claims of the present invention, the whiteness and dingy cleaning performance of the laundry detergent powder product is improved. In addition, the inventors have found that this specific particle architecture also provides a more even distribution of hueing agent on the fabric surface and minimizes any undesirable spotting negatives.